Japanese Patent Application Publication No. 2010-132000 discloses a miter saw including a base portion on which a workpiece is mountable, a cutting unit, and a support portion. The cutting unit includes a saw blade and a motor for rotating the saw blade. The support portion is configured to support the cutting unit at a position above the base portion such that the cutting unit is slidably movable in a direction parallel to an upper surface of the base portion and perpendicular to an axis of the saw blade. The support portion includes a rod extending in the sliding direction, and a slide-support portion supporting the cutting unit and movable in the sliding direction and slidably supported to the rod through a bearing portion. The bearing portion has each end provided with a seal member.